Filling elements and filling systems for filling containers with a liquid filling-material are known. Since oxygen in the air can harm product quality, many of these filling systems expel air from the container before filling it. One way to do this is to seal a container tightly against the filling element before filling it, and flushing the container's interior with a flushing gas. A suitable flushing gas is an inert gas, for example, CO2 gas or nitrogen.
Flushing usually takes place by introducing a gas or flushing tube that can be lowered into the container's interior. This flushing tube introduces flushing gas into the container's interior. To optimize flushing, it is best to insert the flushing tube as far into the container as possible.
A return-gas tube surrounds the flushing tube to form a return-gas channel between the flushing tube and the return-gas tube. This return-gas channel opens into a gas chamber in the filling element and is part of a controlled gas path.